The mission of the UCLA-Caltech MSTP is to promote the education of outstanding physician-scientists. To fulfill this mission, our current goals are to 1) recruit exceptionally bright and accomplished students who exhibit an unusual degree of passion for scientific knowledge and a life-long commitment to research and leadership, 2) help guide admitted students toward outstanding training environments that encourage individual thinking and provide students with the tools needed to develop into accomplished physician-scientists, 3) provide a comprehensive support system to meet the trainees' needs and 4) play an increasingly prominent role in guiding the career development of undergraduate students from under-represented ethnic groups and disadvantaged backgrounds. To accomplish these goals as effectively as possible, the UCLA-Caltech MSTP is run by two equal Co-Directors, three Associate Directors, and a strong administrative team, all of whom are deeply committed to the Program. The Program is structured for an average of eight years of study. An integrated, problem-based medical school curriculum is particularly well suited for MSTP students, due to increased time for independent exploration and increased emphasis on research advances that contributed to current knowledge of disease etiology, diagnosis, and treatment. For their Ph.D. research, students choose mentors from a wide array of science and engineering Ph.D. Programs. The MSTP's commitment to excellence was perhaps most apparent when UCLA and Caltech entered into an affiliation agreement fifteen years ago. This affiliation, which provides an opportunity for two students per year to perform their thesis research at Caltech, not only has increased the number of outstanding mentors available to students, but also appears to have increased the Program's visibility and recruitment success. Substantial institutional support from the David Geffen School of Medicine at UCLA and from Caltech has permitted an increase in the size of the MSTP, with 97 students currently enrolled in the program. The MSTP derives great benefit from recent dramatic improvements in physical facilities at both UCLA and Caltech, from the financial health of the universities, and from the recruitment of a large number of outstanding new faculty members to UCLA and Caltech.